Battery pack and electric vehicle

ABSTRACT

A battery pack and an electric vehicle are provided. The battery pack includes a housing; and a plurality of cells, provided in the housing, wherein the sum V1 of the volumes of the plurality of cells and the volume V2 of the battery pack satisfy V1/V2≥55%. The battery pack has a first direction and a second direction perpendicular to each other. A length direction of the cell is arranged along the first direction of the battery pack, and the plurality of cells are arranged along the second direction of the battery pack. The cell comprises a cell body, and the length of the cell body is 400-2500 mm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application SerialNos. “201910021244.0”, “201910020967.9”, “201910021246.X”,“201910021248.9”, “201910021247.4”, and “201910020925.5”, filed by BYDCompany Limited on Jan. 9, 2019. The entire content of theabove-referenced applications is incorporated herein by reference.

FIELD

This application relates to the technical field of batteries, and inparticular, to a battery pack and an electric vehicle having the batterypack.

BACKGROUND

Battery packs applied to, for example, electric vehicles in the relatedart mainly include a housing and a plurality of battery modules mountedin the housing. Each of the battery modules is formed by a plurality ofcells assembled together.

Users' requirements on the battery life of electric vehicles arebecoming higher. However, in the case of limited space at the bottom ofthe vehicle body, power battery packs in the prior art have the problemof low space utilization and the energy density of such power batterypacks cannot meet the requirements, which gradually becomes an importantfactor hindering the development of electric vehicles.

SUMMARY

In the related art, as shown in FIG. 1, a housing 200″ of a battery pack10′ is often divided into a plurality of mounting regions for batterymodules 400′ by width-direction transverse beams 500′ andlength-direction transverse beams 600′. For example, the battery modules400′ in the battery pack disclosed in CN107925028A are fixed on thewidth-direction transverse beams 500′ or the length-direction transversebeams 600′ by screws or other means. The battery module 400′ includes aplurality of cells arranged in sequence. A plurality of cells arearranged to form a cell array. End beams and/or side beams are disposedoutside the cell array. Usually, both end beams and side beams aredisposed. The end beams and the side beams are fixed to define a spacefor accommodating the cell array. In addition, the end beams and theside beams are connected by screws, or by other connecting members suchas a pull rod, so as to fix the cell array.

The applicant finds through experiments and analysis that because thebattery modules 400′ are fixed on the width-direction transverse beams500′ or the length-direction transverse beams 600′ by screws, space iswasted, and the use of screws or other connecting members increases theweight, reducing the energy density. In addition, because the batterymodules 400′ are designed with the end beams and side beams which allhave a certain thickness and height, space inside the housing 200″ iswasted, leading to low utilization of the volume of the housing 200″.Generally, for the battery pack 10′ in the prior art, the ratio of thesum of the volumes of cells in the housing 200″ to the volume of thehousing 200″ is about 50%, or even lower than 40%.

For the battery pack 10′ provided in the prior art, the end beams andthe side beams of the battery module 400′ and the connection andmounting manners inside the battery pack 10′ reduce the utilization ofthe space inside the housing 200″. As a result, in the battery pack 10′,the ratio of the sum of the volumes of cells to the volume of thehousing 200″ is too low, and the energy density cannot meet theincreasing requirements of users on the battery life of electricvehicles, which gradually becomes an important factor hindering thedevelopment of electric vehicles. In addition, a complicated assemblyprocess is required, and complex assembly procedures need to beperformed. To be specific, first, cells need to be assembled to form abattery module, and then the battery module needs to be mounted in thehousing, leading to increased labor and material costs. In addition,multiple assembly procedures required in the assembly process of thebattery pack lead to an increase in defect rate and an increase in thepossibility of loosening and unstable mounting of the battery pack,adversely affecting the quality of the battery pack and reducing thestability and reliability of the battery pack.

This application is intended to resolve at least one of the technicalproblems existing in the prior art. In view of this, an object of thepresent application is to provide a battery pack, which has theadvantages of high space utilization, high energy density, long batterylife, high reliability, low cost, and high quality.

The present invention also provides an electric vehicle having thebattery pack.

According to an embodiment in a first aspect of the present invention, abattery pack is provided. The battery pack includes a housing; and aplurality of cells, provided in the housing, where the sum V1 of thevolumes of the plurality of cells and the volume V2 of the battery packsatisfy V1/V2≥55%. The battery pack has a first direction and a seconddirection perpendicular to each other. A length direction of the cell isarranged along the first direction of the battery pack, and theplurality of cells are arranged along the second direction of thebattery pack. The housing accommodates only one cell along the firstdirection. The cell includes a cell body, and the length of the cellbody is 600-2500 mm.

In the power battery according to the embodiment of the presentapplication, by limiting the ratio of the sum of the volumes of thecells to the volume of the battery pack, that is, V1/V2, to be ≥55%, thespace utilization of the battery pack is improved, and more cells can bearranged in the battery pack. That is, more energy supply structures arearranged in the unit space to increase the energy density, therebyincreasing the battery life without expanding the occupied space.Moreover, in the process of assembling the battery pack, the cost isreduced, and the quality and reliability of the battery pack areimproved.

According to an embodiment in a second aspect of the presentapplication, an electric vehicle is provided, which includes the batterypack according to the embodiment in the first aspect of the presentapplication.

In the electric vehicle according to the embodiment of the presentapplication, the battery life can be improved without expanding thespace occupied by the battery by using the battery pack according to theembodiment in the first aspect of the present application.

According to an embodiment in a third aspect of the present application,an energy storage device is provided, which includes the battery packaccording to the embodiment in the first aspect of the presentapplication.

Other aspects and advantages of this application will be given in thefollowing description, some of which will become apparent from thefollowing description or may be learned from practices of thisapplication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a battery pack provided in the prior art.

FIG. 2 is a cross-sectional view of a battery pack according to anembodiment of this application.

FIG. 3 is a three-dimensional diagram of a battery pack according to anembodiment of this application.

FIG. 4 is an exploded view of a battery pack according to an embodimentof this application.

FIG. 5 is a schematic structural diagram of a cell according to anembodiment of this application.

FIG. 6 is a schematic view showing the manner of arrangement of batterymodules in a battery pack according to an embodiment of thisapplication.

FIG. 7 is a schematic view showing the manner of arrangement of batterymodules in a battery pack according to another embodiment of thisapplication.

FIG. 8 is a schematic structural diagram of an electric vehicle formedto having a housing of a battery pack according to an embodiment of thisapplication.

FIG. 9 is a schematic structural diagram of an electric vehicleaccording to an embodiment of this application.

FIG. 10 is an exploded view of an electric vehicle according to anembodiment of this application.

FIG. 11 is an enlarged view of region G in FIG. 2.

FIG. 12 is a three-dimensional diagram of a battery pack according to afirst optional embodiment of this application.

FIG. 13 is a three-dimensional diagram of a battery pack according to asecond optional embodiment of this application.

FIG. 14 is a three-dimensional diagram of a battery pack according to athird optional embodiment of this application.

FIG. 15 is a three-dimensional diagram of a battery pack according to afourth embodiment of this application.

FIG. 16 is a three-dimensional diagram of a battery pack according to afifth optional embodiment of this application.

REFERENCE NUMERALS Related Art

-   -   10′ battery pack, 200″ housing, 400′ battery module, 600′        length-direction transverse beam, 500′ width-direction        transverse beam

This application:

-   -   1 electric vehicle,    -   10 battery pack,    -   100 cell, 110 cell body, 200 housing, 210 tray, 220 upper cover,        201 first side beam, 202 second side beam, 203 first end beam,        204 second end beam, 222 exhaust passage, 221 gas inlet    -   400 battery module    -   101 first electrode tab, 102 second electrode tab, 103        anti-explosion valve,    -   600 length-direction transverse beam, 500 width-direction        transverse beam    -   A length direction of battery pack 10, B width direction of        battery pack 10, C height direction of battery pack 10    -   L length of cell body 110, H width of cell body 110, D thickness        of cell body 110, W width of vehicle body, F width of housing        200.

DETAILED DESCRIPTION

Embodiments of this application are described in detail below, andexamples of the embodiments are shown in accompanying drawings, wherethe same or similar elements or the elements having same or similarfunctions are denoted by the same or similar reference numeralsthroughout the description. The embodiments described below withreference to the accompanying drawings are exemplary and used only forexplaining this application, and should not be construed as a limitationon this application.

In the description of this application, it should be understood thatorientation or position relationships indicated by the terms such as“vertical”, “transverse”, “length”, “width”, “thickness”, “inside”, and“outside” are based on orientation or position relationships shown inthe accompanying drawings, and are used only for ease and brevity ofillustration and description, rather than indicating or implying thatthe mentioned apparatus or component must have a particular orientationor must be constructed and operated in a particular orientation.Therefore, such terms should not be construed as limiting of thisapplication.

In addition, in the description of this application, “a plurality of”means two or more than two.

Considering the status of battery packs in the related art, thisapplication provides a battery pack and an electric vehicle having thebattery pack. The battery pack has the advantages of high spaceutilization, high energy density, and long battery life.

A battery pack 10 according to an embodiment of this application isdescribed with reference to accompanying drawings.

As shown in FIGS. 2-16, the battery pack 10 according to an embodimentof the present application includes a housing 200 and a plurality ofcells 100.

The plurality of cells 100 are provided in the housing 200, and thehousing 200 can be understood as a housing for accommodating theplurality of cells 100. For example, it may include a tray 210 and anupper cover 220. The tray 210 and the upper cover 220 work together todefine a space accommodating the plurality of cells 100. The pluralityof cells 100 are provided in the tray 210, and are covered by the uppercover 220. The sum V1 of the volumes of the plurality of cells 100 andthe volume V2 of the battery pack 10 satisfy V1/V2≥55%.

Those skilled in the art can understand that V1 is the product of thevolume of each cell 100 and the number of cells 100, that is, V1 is thetotal volume of the plurality of cells 100; and V2 is the overall volumeof a three-dimensional shape defined by an external profile of thebattery pack 10.

In the battery pack 10 according to the embodiment of the presentapplication, by limiting the ratio of the sum V1 of the volumes of thecells 100 to the volume V2 of the battery pack 10, that is, V1/V2, to be≥55%, the space utilization of the battery pack 10 is improved, and morecells 100 can be arranged in the battery pack 10. That is, more energysupply structures are arranged in the unit space to increase the energydensity, thereby increasing the battery life without expanding theoccupied space. Moreover, in the process of assembling the battery pack,the cost is reduced, and the quality and reliability of the battery packare improved. In the battery pack provided in this application, thehousing accommodates only one cell along a first direction. The cellincludes a cell body, and the length of the cell body is 600-2500 mm andis arranged along the first direction in the battery pack. The pluralityof cells are arranged along the second direction. The long cells arearranged and located in the battery pack, to form a battery pack havinga volume utilization of 55% or higher. In this way, the spaceutilization, the energy density and the battery life of an electricvehicle using the battery pack are improved.

In some specific embodiments of this application, the ratio of the sumV1 of the volumes of the cells 100 to the volume V2 of the battery pack10 satisfy V1/V2≥60%.

In some other specific embodiments of this application, the ratio of thesum V1 of the volumes of the cells 100 to the volume V2 of the batterypack 10 satisfy V1/V2≥62%.

In some other specific embodiments of this application, the ratio of thesum V1 of the volumes of the cells 100 to the volume V2 of the batterypack 10 satisfy V1/V2≥65%.

It can be understood that V2 is the overall volume of athree-dimensional shape defined by an external profile of the batterypack 10, that is, a volume including the internal space of the batterypack 10, a volume of the three-dimensional area enclosed in space by theexternal profile of the battery pack 10. In electric vehicles, V1/V2 canbe understood as space utilization.

Those skilled in the art can understand that due to some factors, forexample, peripheral components will occupy the internal space of thehousing 200, including an anti-collision space at a bottom of the tray,a liquid cooling system, a thermal insulation material, an insulationprotection, an accessory for thermal safety, a flame exhaust passage,and a high-voltage power distribution module, etc., so the peak value ofV1/V2 is usually 80%, that is, V1/V2≤80%.

The battery pack 10 according to a specific embodiment of the presentapplication is described below with reference to the drawings, in whicha length direction of the battery pack 10 is indicated by an arrow A, awidth direction of the battery pack 10 is indicated by an arrow B, and aheight direction of the battery pack 10 is indicated by an arrow C.

In some specific embodiments of the present application, as shown inFIGS. 2 to 4, a length direction of the cell 100 is arranged along thewidth direction B of the battery pack 10, and a plurality of cells 100are arranged along the length direction A of the battery pack 10, thuspromoting V1/V2 of the battery pack 10 to increase to 55%, 60%, 62%, 65%or higher. Moreover, to reserve enough space for mounting otherelectronic components (such as battery management system, BMS),generally the space utilization of the battery pack 10 is set below 85%.

In some specific embodiments of the present application, as shown inFIGS. 3 and 4, in the width direction B of the battery pack 10, adistance from the cell 100 to sidewalls of the housing 200 is less thanthe length of the cell 100. Specifically, in the width direction B ofthe battery pack 10, a shortest distance from one end of the cell 100 toa side beam of the housing 200 adjacent to the end of the cell 100 isL1, a shortest distance from the other end of the cell 100 to a sidebeam of the housing 200 adjacent to the other end of the cell 100 is L2,and the length L of the cell 100 satisfies: L1+L2<L. In this way, thebattery pack 10 cannot additionally accommodate another cell 100 in thewidth direction B.

In other words, the housing 200 accommodates only one cell 100 in thewidth direction B of the battery pack 10. That is, in the widthdirection B of the battery pack 10, the cell 100 cannot be arranged in apattern including two or more cells. When at least two layers of cells100 are provided in the battery pack 10 along the height direction C ofthe battery pack 10, at least one layer of cells 100 can accommodateonly one cell in the width direction B of the battery pack 10. Thedescription “accommodate only one cell 100” means that in the widthdirection B of the battery pack 10, only one cell 100 can be arrangedside by side. However, in the height direction C of the battery pack 10,although two layers of cells can be provided, it is not intended toarrange more than one cell 100 in the width direction B of the batterypack 10.

It can be understood that in the width direction B of the battery pack10, side beams are provided at two sides of the housing 200; and in thelength direction A of the battery pack 10, end beams are provided at twoends of the housing 200.

In some specific embodiments of this application, as shown in FIGS. 3and 4, the length of the cell 100 extends across the entire widthdirection B of the battery pack 10. That is, along the width direction Bof the battery pack 10, the cell 100 extends from one side to the otherside of the housing 200, and the length of the cell 100 is filled in thewidth direction B of the battery pack 10. The housing 200 cannotaccommodate two or more cells 100 in the width direction B of thebattery pack 10. Two ends of the cell 100 in the length direction can befitted to the two opposite side walls of the housing 200 in the widthdirection B, for example, fixed to the housing 200. As a result, nowidth-direction transverse beams and length-direction transverse beamsare required in the housing 200, and the connected cells 100 candirectly act as the intermediate beams. This greatly simplifies thestructure of the housing 200, and reduces the space occupied by theintermediate beams and by structures for mounting the cells 100, therebyimproving the space utilization and improving the battery life.

The embodiments of the present application are not limited to notproviding width-direction transverse beams and length-directiontransverse beams. In some embodiments of the present application, asshown in FIG. 13, a width-direction transverse beam 500 can be providedin the housing 200. The width-direction transverse beam 500 extendsalong the width direction B of the battery pack 10, and a plurality ofcells 100 are arranged along the length direction A of the battery pack10 to form a battery array. The width-direction transverse beam 500divides the battery array into at least two parts along the lengthdirection A of the battery pack 10. Each part of the battery arrayincludes at least one cell 100, and each part of the battery arrayconstitutes a battery module 400.

In some other embodiments of the present application, as shown in FIG.12, a length-direction transverse beam 600 can also be provided in thehousing 200. The length-direction transverse beam 600 extends along thelength direction A of the battery pack 10. The length direction of thecell 100 is arranged along the width direction B of the battery pack 10.A plurality of cells 100 are arranged along the length direction A ofthe battery pack 10 to form a battery array. At least two rows ofbattery arrays are arranged in the housing 200 along the width directionB of the battery pack 10. Each row of battery array includes a pluralityof cells 100 arranged along the length direction A of the battery pack10. The length-direction transverse beam 600 is located between twoadjacent rows of battery arrays.

In some specific embodiments of this application, the housing 200includes side beams located at two sides of the battery pack 10 in thewidth direction B, and both ends in the length direction of the cell 100are supported by the side beams. The housing 200 includes end beamslocated at two ends of the battery pack 10 in the length direction A,and the end beams provide an inward pressing force against the cell 100adjacent to them.

As shown in FIGS. 3 and 4, the housing 200 has a first side beam 201, asecond side beam 202, a first end beam 203 and a second end beam 204.The first side beam 201, the second side beam 202, the first end beam203 and second end beam 204 are sequentially connected end to end. Thefirst side beam 201 and the second side beam 202 are opposite in thewidth direction B of the battery pack 10, and the first end beam 203 andthe second end beam 204 are opposite in the length direction A of thebattery pack 10. The first side beam 201 and the second side beam 202provide support for the two ends of the cell 100 in the lengthdirection, that is, one end of the cell 100 is supported by the firstside beam 201 and the other end is supported by the second side beam202. The first end beam 203 and the second end beam 204 provide apressing force against two sides of the cell 100 in the thicknessdirection. That is, the first end beam 203 applies a force toward thesecond end beam 204 to the cell 100 arranged adjacent to the first endbeam 203, and the second end beam 204 applies a force toward the firstend beam 203 to the cell 100 arranged adjacent to the second end beam204, to allow a plurality of cells 100 to be tightly arranged betweenthe first end beam 203 and the second end beam 204 along the lengthdirection A of the battery pack 10, where the plurality of cells 100 fitto each other. In addition, the first end beam 203 and the second endbeam 204 can limit the plurality of cells 100 in the length direction Aof the battery pack 10. Particularly when the cell 100 expands slightly,they can buffer and provide an inward pressing force against the cell100, to prevent excessive expansion and deformation of the cell 100.

In some specific embodiments of the present application, as shown inFIG. 7, the length direction of the cell 100 is arranged along the widthdirection B of the battery pack 10, and a plurality of cells 100 arearranged along the length direction A of the battery pack 10 to form abattery array. There are at least two layers of battery arrays in thehousing 200 along the height direction C of the battery pack 10. As aresult, the number of cells 100 is optimized, whereby the spaceutilization is increased to increase the energy density, and BIC andlow-voltage sampling are easier to be integrally implemented.

In some specific embodiments of the present application, as shown inFIGS. 15 and 16, the length direction of the cell 100 is arranged alongthe length direction A of the battery pack 10, and a plurality of cells100 are arranged along the width direction B of the battery pack 10.This leads to a space utilization of the battery pack 10 of 55%, 60%,62%, 65% or higher.

In some specific embodiments of the present application, as shown inFIGS. 15 and 16, in the length direction A of the battery pack 10, adistance from the cell 100 to end walls of and the housing 200 is lessthan the length of the cell 100. Specifically, in the length direction Aof the battery pack 10, a shortest distance from one end of the cell 100to an end beam of the housing 200 adjacent to the end of the cell 100 isL3, a shortest distance from the other end of the cell 100 to an endbeam of the housing 200 adjacent to the other end of the cell 100 is L4,and the length L of the cell 100 satisfies: L3+L4<L. In this way, thebattery pack 10 cannot additionally accommodate another cell 100 in thelength direction A.

In other words, the housing 200 accommodates only one cell 100 in thelength direction A of the battery pack 10. That is, in the lengthdirection A of the battery pack 10, the cell 100 cannot be arranged in apattern including two or more cells.

It can be understood that in the width direction B of the battery pack10, side beams are provided at two sides of the housing 200; and in thelength direction A of the battery pack 10, end beams are provided at twosides of the housing 200.

In some specific embodiments of this application, as shown in FIGS. 15and 16, the length of the cell 100 extends across the entire lengthdirection A of the battery pack 10. That is, along the length directionA of the battery pack 10, the cell 100 extends from one end to the otherend of the housing 200, and the length of the cell 100 is filled in thelength direction A of the battery pack 10. The housing 200 cannotaccommodate two or more cells 100 in the length direction A of thebattery pack 10. Two ends of the cell 100 in the length direction can beengaged to the two opposite end walls of the housing 200 in the lengthdirection A, for example, fixed to the housing 200. As a result, nowidth-direction transverse beams and length-direction transverse beamsare required in the housing 200, and the connected cells 100 candirectly act as the intermediate beams. This greatly simplifies thestructure of the housing 200, and reduces the space occupied by theintermediate beams and by structures for mounting the cells 100, therebyimproving the space utilization and improving the battery life.

The embodiments of the present application are not limited to notproviding length-direction transverse beams and width-directiontransverse beams. In some embodiments of the present application, asshown in FIG. 15, a length-direction transverse beam 600 can be providedin the housing 200. The length-direction transverse beam 600 extendsalong the length direction A of the battery pack 10, and a plurality ofcells 100 are arranged along the width direction B of the battery pack10 to form a battery array. The length-direction transverse beam 600divides the battery array into at least two parts along the widthdirection B of the battery pack 10. Each part of the battery arrayincludes at least one cell 100, and each part of the battery arrayconstitutes a battery module 400.

In some other embodiments of the present application, a width-directiontransverse beam 500 can also be provided in the housing 200. Thewidth-direction transverse beam 500 extends along the width direction Bof the battery pack 10. The length direction of the cell 100 is arrangedalong the length direction A of the battery pack 10. A plurality ofcells 100 are arranged along the width direction B of the battery pack10 to form a battery array. At least two rows of battery arrays arearranged in the housing 200 along the length direction A of the batterypack 10. Each row of battery array includes a plurality of cells 100arranged along the width direction B of the battery pack 10. Thewidth-direction transverse beam 500 is located between two adjacent rowsof battery arrays.

In some specific embodiments of this application, the housing 200includes end beams located at two ends of the battery pack 10 in thelength direction A, and both ends in the length direction of the cell100 are supported by the end beams. The housing 200 includes side beamslocated at two sides of the battery pack 10 in the width direction B,and the side beams provide an inward pressing force against the cell 100adjacent to them.

As shown in FIG. 16, the housing 200 has a first side beam 201, a secondside beam 202, a first end beam 203 and a second end beam 204. The firstside beam 201, the second side beam 202, the first end beam 203 andsecond end beam 204 are sequentially connected end to end. The firstside beam 201 and the second side beam 202 are opposite in the widthdirection B of the battery pack 10, and the first end beam 203 and thesecond end beam 204 are opposite in the length direction A of thebattery pack 10. The first end beam 203 and the second end beam 204provide support for the two ends of the cell 100 in the lengthdirection, that is, one end of the cell 100 is supported by the firstend beam 203 and the other end is supported by the second end beam 204.The first side beam 201 and the second side beam 202 provide a pressingforce against two sides of the cell 100 in the thickness direction. Thatis, the first side beam 201 applies a force toward the second side beam202 to the cell 100 arranged adjacent to the first side beam 201, andthe second side beam 202 applies a force toward the first side beam 201to the cell 100 arranged adjacent to the second side beam 202, to allowa plurality of cells 100 to be tightly arranged between the first sidebeam 201 and second side beam 202 along the width direction B of thebattery pack 10, where the plurality of cells 100 fit to each other. Inaddition, the first side beam 201 and the second side beam 202 can limitthe plurality of cells 100 in the width direction B of the battery pack10. Particularly when the cell 100 expands slightly, they can buffer andprovide an inward pressing force against the cell 100, to preventexcessive expansion and deformation of the cell 100.

In some specific embodiments of the present application, as shown inFIG. 15, the length direction of the cell 100 is arranged along thelength direction A of the battery pack 10, and a plurality of cells 100are arranged along the width direction B of the battery pack 10 to forma battery array. There is at least one layer of battery arrays in thehousing 200 along the height direction C of the battery pack 10. As aresult, the number of cells 100 is optimized, whereby the spaceutilization is increased to increase the energy density, and BIC andlow-pressure sampling are easier to be integrally implemented.

In some specific embodiments of the present application, a plurality ofcells 100 can be assembled into multiple battery modules 400. Themultiple battery modules 400 can be arranged along the length directionA of the battery pack 10 (as shown in FIG. 6), the multiple batterymodules 400 can also be arranged along the width direction B of thebattery pack 10 (as shown in FIG. 15), or the multiple battery modules400 can also be arranged along the height direction C of the batterypack 10 to form a multilayer structure (as shown in FIG. 7). In otherwords, regardless of the cells 100 extending along the width direction Bor the length direction A of the battery pack 10, the plurality of cells100 can be arranged in multiple layers along the height direction C ofthe battery pack 10. The multiple battery modules 400 can also bearranged along both the length direction A and the height direction C ofthe battery pack 10, or along both the width direction A and the heightdirection C of the battery pack 10. As a result, the number of batterymodules 400 is optimized, whereby the space utilization is increased toincrease the energy density, and BIC and low-voltage sampling are easierto be integrally implemented. It should be understood that the batterymodule 400 in the embodiment of the present application does not havestructures such as end beams and side beams.

In the related art, due to the small size and short length of the cell,the two opposite ends of the cell cannot be fitted to the two oppositeside walls of the housing 200″. Therefore, the length-directiontransverse beams 600′ and/or the width-direction transverse beams 500′(as shown in FIG. 1) is/are needed to be provided in the housing 200″,to facilitate the cell assembly. When the cells are mounted in thehousing 200″ by means of the battery modules 400′, there will bemultiple cells along the width direction of the battery pack 10′. Thatis, the cell does not extend between the two opposite side walls, butextend between two opposite length-direction transverse beams 600′ orwidth-direction transverse beams 500′. The battery module is fixed to anadjacent length-direction transverse beam 600′ and/or width-directiontransverse beams 500′ by a fastener.

Since the length-direction transverse beams 600′ and/or thewidth-direction transverse beams 500′ are provided in the housing 200″in the related art, the length-direction transverse beams 600′ and/orthe width-direction transverse beams 500′ occupy a large mounting spacefor accommodating the cells in the housing 200″, causing a low spaceutilization of the housing 200″. Generally, the ratio of the sum of thevolumes of cells to the volume of the housing 200″ is about 40%, or evenlower. In other words, only about 40% of the space in the housing 200″in the related art is available for mounting the cells, resulting in alimited number of cells accommodated in the housing 200″, limitedcapacity and voltage of the entire battery pack 10′, and poor batterylife of the battery pack 10′.

The battery pack 10 according to the embodiments of the presentapplication can, on the one hand, reduce the use of length-directiontransverse beams and/or width-direction transverse beams in the housing200. Even the length-direction transverse beams and/or thewidth-direction transverse beams may be not provided in the housing 200,to reduce the space occupied by the length-direction transverse beamsand/or the width-direction transverse beams in the housing 200, andimprove the space utilization of the housing 200. On the other hand, itcan reduce the use of end beams and side beams in the battery module400, and reduce the space occupied by the end beams and the side beamsin the housing 200, to improve the space utilization of the housing 200.As many cells 100 as possible are arranged in the housing 200, toincrease the capacity, voltage and battery life of the entire batterypack.

Moreover, since no length-direction transverse beams and/orwidth-direction transverse beams are needed to be arranged in thehousing 200, on the one hand, the manufacturing process of the housing200 is simplified, the assembly complexity of cells 100 is reduced, andthe production cost is reduced; and on the other hand, the weights ofthe housing 200 and the entire battery pack 10 are reduced, achieving alight weight of the battery pack 10. In particular, when the batterypack 10 is mounted on an electric vehicle, the battery life of theelectric vehicle is improved, and a light weight of the electric vehicleis achieved.

In addition, the cell 100 itself can be used to strengthen thestructural strength of the housing 200. That is, there is no need toprovide a strengthening structure for enhancing the structural strengthin the housing 200, and the cell 100 itself can directly replace thestrengthening structure to ensure the structural strength of the housing200, thus ensuring that the housing 200 is not prone to deformationunder the action of an external force. Compared with the battery packdisclosed in Chinese Patent Document CN107925028A, the housing 200 cannot only accommodate and protect the cells 100, but also support thecells 100 to improve the overall load-bearing capacity of the batterypack 10. The length of the cell 100 enhances the strength of the batterypack 10. In addition, the surface area of a single cell 100 isincreased, to increase the heat dissipation area and increase the heatdissipation rate of the cell 100, thereby improving the safety of theentire battery pack 10 and making the battery pack 10 safer and morereliable.

In some specific embodiments of this application, the cell 100 includesa cell body 110 (which can be understood as a body part excludingsmall-sized protruding structures such as electrode tabs), and thevolume V of the cell body 110 and the energy E of the cell body 110satisfy: V/E≤2000 mm³·Wh⁻¹. Therefore, it is possible to ensure asufficient heat dissipation area to ensure the heat dissipation effect,and reduce the volume ratio of the cells 100, which is beneficial to thecompact arrangement of a plurality of cells 100 in the battery pack 10.

In some specific embodiments of the present application, as shown inFIGS. 9 and 10, the housing 200 is different from the battery packhousing disclosed in Chinese Patent Document CN107925028A, especially interms of the size and load bearing capacity. The housing 200 includes avehicle tray 210 that is fitted and connected to a vehicle body, to forma structure fitted to the vehicle body for accommodating and carryingthe cells 100. The vehicle tray 210 is a separately produced tray foraccommodating and mounting the cells 100. After the cell 100 is mountedin the vehicle tray 210, the vehicle tray 210 can be mounted to thevehicle body by a fastener. For example, the vehicle tray is hanged on achassis of an electric vehicle, to accommodate and bear the cells.

When the battery pack 10 is used as a battery pack for providingelectric energy on a vehicle, the length direction of the cell 100 canbe arranged along a length direction of the vehicle body, that is, thefront and rear directions of the vehicle. At this time, the length L ofthe cell body 110 of the cell 100 may be 400-2500 mm. In someembodiments, L may be 400-1500 mm, so that the length of the cell 100can be adapted to the length of the vehicle. When the battery pack 10 isused as a battery pack for providing electric energy on a vehicle, thelength direction of the cell 100 can be arranged along a width directionof the vehicle body, that is, the left and right directions of thevehicle. At this time, the length L of the cell body 110 of the cell 100may be 400-1500 mm, so that the length of the cell 100 can be adapted tothe width of the vehicle. In some embodiments of the presentapplication, the length L of the cell body is 700-2500 mm. Further, thelength L of the cell body may be 800-1500 mm.

In some specific embodiments of the present application, as shown inFIG. 8, the housing 200 may also be directly formed on the electricvehicle, that is, the housing 200 is a device for mounting the cells 100and formed at any appropriate position on the electric vehicle. Forexample, the housing 200 may be formed on the chassis of the electricvehicle.

In some specific embodiments of the present application, when thebattery pack 10 is arranged on an electric vehicle, unlike the batterypack disclosed in Chinese Patent Document CN107925028A, the battery pack10 also includes at least one of a battery management system (BMS), abattery connector, a battery sampler, a battery thermal managementsystem, and other components required for the vehicle battery. The widthdirection B of the battery pack 10 is arranged along the width directionof the vehicle body, that is, the left and right directions of thevehicle; and the length direction of the battery pack 10 is arrangedalong the length direction of the vehicle body, that is, the front andrear directions of the vehicle. The present application is not limitedthereto. The width direction B of the battery pack 10 may be arrangedalong the length direction of the vehicle body, and the length directionA of the battery pack 10 may be arranged along the width direction ofthe vehicle body. In some embodiments of the present application, thefirst direction and the second direction are two directionsperpendicular to each other with the battery pack as a reference. Thefirst direction may be the width direction of the battery pack, and thesecond direction may be the length direction of the battery pack.

Those skilled in the art can understand that the orientation of thecells 100 in the battery pack 10 and the orientation of the battery pack10 on the electric vehicle can be combined in various forms. Forexample, the length direction of the cell 100 can be arranged along thewidth direction B of the battery pack 10 or along the length direction Aof the battery pack 10. The width direction B of the battery pack 10 canbe arranged along the width direction of the vehicle body or along thelength direction of the vehicle body. For example, regardless of thewidth direction B of the battery pack 10 being arranged along the widthdirection of the vehicle body or along the length direction of thevehicle body, the length direction of the cell 100 is arranged along thewidth direction of the vehicle body. The relative direction ofarrangement of the cell 100, the battery pack 10 and the vehicle bodycan be arranged according to the practical application to meet variousrequirements.

The cell 100 according to an embodiment of the present application willbe described below with reference to the accompanying drawings.

In the following specific embodiments, the length L, the width H and thethickness D are in millimeters (mm), the surface area S is in squaremillimeter (mm²), the volume V is in cubic millimeter (mm³), and theenergy E is in watt-hour (Wh).

As shown in FIG. 5, the cell 100 according to an embodiment of thepresent application includes a cell body 110. It can be understood thatthe cell body 110 is a body part excluding small-sized protrudingstructures such as electrode tabs. The cell body 110 has a length L, awidth H, and a thickness D.

The length L of the cell body 110 is greater than the width H of thecell body 110, the width H of the cell body 110 is greater than thethickness D of the cell body 110, and the length L of the cell body 110and the width H of the cell body 110 satisfy: L/H=4-21. In some specificembodiments of the present application, the length L of the cell body110 and the width H of the cell body 110 satisfy: L/H=9-13.

In the development of electric vehicles, the voltage platformrequirement for the cells are predetermined, which makes the volume ofthe cell a fixed value. That is, when a certain voltage platform isreached, the amount of materials contained in the cell is constant, andthus the volume is constant, on the basis of use of materials of thesame chemical system. In the cell 100 according to the embodiment of thepresent application, by designing the ratio of the length L to the widthH of the cell body 110, the cell body 110 can be reasonably flattenedand elongated at a given certain volume. On the one hand, this isconducive to the overall arrangement in the battery pack (for example,the arrangement of the battery pack 10 according to the above-mentionedembodiment of the present application), thereby improving the spaceutilization, enhancing the energy density, and thus increasing thebattery life of the battery pack. On the other hand, this can ensurethat the cell 100 has a large enough heat dissipation area to transferthe internal heat to the outside in time to prevent the heat fromaccumulating inside, thereby forming a higher energy density andsupporting the improvement of battery life.

According to some specific embodiments of the present application, tooptimize the arrangement of the cell 100 in the battery pack and improvethe heat dissipation capacity of the cell 100, the length L and thethickness D of the cell body 110 satisfy: L/D=23-208. In someembodiments, L/D=23-200. According to some other specific embodiments ofthe present application, the length L and the thickness D of the cellbody 110 satisfy: L/D=50-120.

In some specific embodiments of the present application, as shown inFIG. 5, the cell body 110 is structured to have a shape of rectangularparallelepiped with a smooth outer surface to have a certain structuralstrength. The cell core of the cell is placed in a prismatic cellcasing, the opening of the cell casing is sealed with a cover plate, andan electrolyte is injected. Compared with the cell with an aluminumlaminated film, the cell 100 according to the embodiment of the presentapplication has good thermal conductivity, and can effectively eliminatethe problem of heat dissipation caused by a large-sized structure, whenused in conjunction with a conventional battery thermal managementstructure. Compared with cylindrical cells, the space utilization ishigher, and the production and assembly processes are simpler.

When the cell 100 according to the embodiment of the present applicationis arranged in the housing 200 of the battery pack 10, the lengthdirection and the thickness direction of the cell body 110 may extend inthe horizontal directions, and the width direction of the cell body 110may extend in the vertical direction. That is, the cell 100 stands onside. The horizontal and vertical directions are based on the directionof the battery pack 10 when it is used (for example, when used in anelectric vehicle).

In some specific embodiments of this application, to optimize thearrangement of the cell 100 in the battery pack 10 to increase theenergy density and increase the battery life, and to make thearrangement of the cell body 110 more compact and the energy moreconcentrated in the limited space of the housing 200, other parametersof the cell 100 are designed.

According to some embodiments of the present application, the length Lof the cell body 110 and the volume V of the cell body 110 satisfy:L/V=0.0005 mm⁻²-0.002 mm⁻². According to some embodiments of the presentapplication, the width H of the cell body 110 and the volume V of thecell body 110 satisfy: H/V=0.0001 mm⁻²-0.00015 mm⁻². According to someembodiments of the present application, the thickness D of the cell body110 and the volume V of the cell body 110 satisfy: D/V=0.0000065mm⁻²-0.00002 mm⁻². For a cell body 110 of a certain volume, the ratio ofeach of the length L, the width H, and the thickness D to the volume Vcan be designed to optimize the spatial distribution of unit energy,thereby facilitating the arrangement in the housing 200.

In some embodiments of the present application, the length L of the cellbody 110 and the surface area S of the cell body 110 satisfy: L/S=0.002mm⁻¹-0.005 mm⁻¹. According to some embodiments of the presentapplication, the length L of the cell body 110 and the energy E of thecell body 110 satisfy: L/E=0.8 mm·Wh⁻¹-2.45 mm·Wh⁻¹. According to someembodiments of the present application, the length L of the cell body110 and the energy E of the cell body 110 satisfy: L/E=1.65 mm Wh⁻¹-2.45mm·Wh⁻¹. As such, the cell 100 is facilitated to extend across twoopposite sides of the housing 200 in its length direction, therebyimproving the battery life of the battery pack 10, while the structuralstrength and heat dissipation effect of the cell 100 are considered.

In some other embodiments of this application, the surface area S of thecell body 110 and the volume V of the cell body 110 satisfy:S/V=0.1-0.35 mm⁻¹. Therefore, it is possible to ensure a sufficient heatdissipation area to ensure the heat dissipation effect, and reduce thevolume ratio of the cells 100, which is beneficial to the compactarrangement of a plurality of cells 100 in the battery pack 10.

The surface area S of the cell body 110 and the energy E of the cellbody 110 satisfy: S/E≤1000 mm²·Wh⁻¹. This can ensure sufficient heatdissipation on the surface of the cell 100. especially when a ternary ora high-nickel ternary cathode material is employed in the power battery,the internal heat of the battery can be conducted in time, which isbeneficial to the battery safety. In addition, the cell 100 in theembodiment of the present application is a prismatic cell with a smoothouter surface, which has a certain structural strength, and has a goodthermal conductivity. Compared with a cell with a corrugated surfacearea, the process and subsequent assembly are less difficult.

In some specific embodiments of the present application, as shown inFIG. 5, the cell 100 further includes a first electrode tab 101 and asecond electrode tab 102.

The first electrode tab 101 is provided at one end of the cell body 110in the length direction, and the second electrode tab 102 is provided atthe other end of the cell body 110 in the length direction. In otherwords, the length direction of the cell 100 may be the current directioninside the cell 100, that is, the current direction inside the cell 100is as indicated by an arrow B. In this manner, since the currentdirection is the same as the length direction of the cell 100, theeffective heat dissipation area of the cell 100 is larger and the heatdissipation efficiency is higher. Here, the first electrode tab 101 maybe a positive electrode tab of the cell 100, and the second electrodetab 102 is a negative electrode tab of the cell 100; or, the firstelectrode tab 101 is the negative electrode tab of the cell 100, and thesecond electrode tab 102 is the positive electrode tab of the cell 100.

In some specific embodiments of the present application, as shown inFIG. 5, the cell 100 further includes at least one anti-explosion valve103.

The at least one anti-explosion valve 103 is provided on at least oneend of the cell body 110 in the length direction. When the cell 100fails and expands, the gas pressure inside is enough to break through aflipping sheet in the at least one anti-explosion valve 103, causing ashort circuit of the cell 100 to ensure the safety of the cell 100, andprevent the cell 100 from explosion.

Those skilled in the art can understand that the arrangement of the atleast one anti-explosion valve 103 can be applied not only to a cellwith an aluminum casing, but also to a pouch cell. In addition, the atleast one anti-explosion valve 103 can also be arranged at otherpositions than the ends of the cell body 100.

In some specific embodiments of the present application, the two ends ofthe cell body 110 in the length direction are respectively provided withan anti-explosion valve 103, and the anti-explosion valves 103 at thetwo ends of the cell body 110 are exhausted via different exhaustpassages 222.

For example, as shown in FIGS. 2, 5 and 11, the cell 100 is providedwith an anti-explosion valve 103 at a first end facing the first sidebeam 201, and the first side beam 201 is provided with exhaust passages222 therein. A gas inlet 221 is provided at a position on the first sidebeam 201 corresponding to the anti-explosion valve 103 of each cell 100,and the gas inlet 221 communicates with the exhaust passage 222. Thehousing 200 is provided with an exhaust vent communicating with theexhaust passage 222. And/or the cell 100 is provided with ananti-explosion valve 103 at a second end facing the second side beam202, and second side beam 202 is provided with exhaust passages 222therein. A gas inlet 221 is provided at a position on the second sidebeam 202 corresponding to the anti-explosion valve 103 of each cell 100,and the gas inlet 221 communicates with the exhaust passage 222. Thehousing 200 is provided with an exhaust vent communicating with theexhaust passage 222.

In the related art, during the use of the cell, if the gas pressureinside the cell increases to a certain degree, the anti-explosion valveis opened, so that the flame, smoke or gas inside the cell will bedischarged through the anti-explosion valve. The flame, smoke or gasaccumulates inside the battery pack, and if not discharged in time, willcause secondary damage to the cell. In the embodiment of the presentapplication, since the first side beam 201 and/or second side beam 202is/are provided with the gas inlet 221 corresponding to theanti-explosion valve 103 of the cell 100, and the first side beam 201and/or second side beam 202 is/are provided the exhaust passage 222therein, the anti-explosion valve is opened when the gas pressure insidethe cell 100 increases, and the flame, smoke or gas inside the cell willdirectly enter the exhaust passages 222 inside the first side beam 201and/or the second side beam 202 through the gas inlet 221, and will bedischarged out of the first side beam 201 and/or the second side beam202 through the exhaust vent, for example, discharged into theatmosphere through the exhaust vent. In this way, the flame, smoke orgas will not accumulate inside the battery pack 200, thereby preventingthe flame, smoke or gas from causing secondary damage to the cell 100.

In addition, one end of each cell 100 in the plurality of cells 100 isexhausted through the exhaust passage 222 in the first side beam 201,and the other end of each cell 100 in the plurality of cells 100 isexhausted through the exhaust passage 222 in the second side beam 202.As a result, the two ends of the cell 100 are exhausted throughdifferent passages, which increases the exhaust distance and formscrossover exhaust, thereby reducing the temperature.

An electric vehicle 1 according to an embodiment of the presentapplication is described below with reference to the accompanyingdrawings. The electric vehicle may include commercial vehicles, specialvehicles, electric bicycles, electric motorcycles, electric scooters,and other electric vehicles which need to be powered by a battery packto provide electrical energy to drive them to travel.

As shown in FIG. 9 and FIG. 10, the electric vehicle 1 according to theembodiment of the present application includes a battery pack 10according to the above-mentioned embodiment of the present application,where the housing 200 can be integrally formed on the electric vehicle,or the housing 200 can also be a separately produced vehicle tray wherethe cell 100 is accommodated and mounted.

In the electric vehicle 1 according to the embodiment of the presentapplication, the battery life can be improved without expanding thespace occupied by the battery by using the battery pack 10 according tothe embodiment of the present application.

In some specific embodiments of the present application, as shown inFIGS. 9 and 10, the battery pack 10 is arranged at a bottom of theelectric vehicle 1, and the housing 200 is fixedly connected to achassis of the electric vehicle 1. Since the mounting space at thechassis of the electric vehicle 1 is large, when the battery pack 10 isprovided on the chassis of the electric vehicle 1, the number of cells100 can be increased as many as possible, thereby increasing the batterylife of the electric vehicle 1.

In some specific embodiments of this application, as shown in FIGS. 9and 10, the electric vehicle 1 includes a battery pack 10 arranged at abottom of the electric vehicle 1. The housing 200 is fixedly connectedto a chassis of the electric vehicle 1. The width direction of thebattery pack 10 extends along a width direction of a vehicle body of theelectric vehicle 1, that is, the left and right directions of theelectric vehicle 1, and the length direction of the battery pack 10extends along a length direction of the vehicle body of the battery pack10, that is, the front and rear directions of the electric vehicle 1. Inother embodiments, the electric vehicle 1 may include a plurality ofbattery packs 10 arranged at the bottom of the electric vehicle 1, andthe shape and size of the plurality of battery packs 10 may be the sameor different. Each battery pack 10 can be adjusted according to theshape and size of the chassis of the electric vehicle 1, and theplurality of battery packs 10 are arranged along the length direction,that is, the front and rear directions of the vehicle body.

In some specific embodiments of the present application, the ratio ofthe width F of the housing 200 to the width W of the vehicle bodysatisfies: 50%≤F/W≤80%. In some other embodiments of the presentapplication, the length L of the cell body in the width direction of thebattery pack and the width W of the vehicle body satisfy: 46%≤L/W≤76%.In the foregoing embodiments, this can be achieved by arranging only onehousing 200 along the width direction of the vehicle body. When thereare multiple housings 200, the multiple housings 200 are arranged alongthe length direction of the vehicle body. Generally, for most vehicles,the width W of the vehicle body is 500-2000 mm, for example, 500 mm,1600 mm, 1800 mm, and 2000 mm, and the length of the vehicle body is500-5000 mm. For a passenger vehicle, the width of the passenger vehicleis usually 500-1800 mm, and the length of the vehicle body is 500-4000mm.

In some other embodiments of the present application, the width F of thehousing 200 is 500-1500 mm, which is much larger than the battery packhousing disclosed in Chinese Patent Document CN107925028A, to facilitatethe accommodation of the battery module 400 in the battery pack inCN107925028A, and ensure the battery life. This size mate with the sizeof the vehicle body.

In some specific embodiments of the present application, the cell 100includes a cell body 110, where the ratio of the length L of the cellbody 110 to the width W of the vehicle body satisfies: 46%≤L/W≤76%. Inthis embodiment, this can be achieved by arranging only one cell 100along the width direction of the vehicle body. In other possibleimplementations, multiple battery modules 400 or multiple cells 100 canbe arranged in the length direction, while such size requirements aremet. In some embodiments, the length L of the cell body 110 is 400-1500mm.

Other configurations and operations of the cell 100, the battery pack10, and the electric vehicle 1 according to the embodiments of thepresent application are known to those of ordinary skill in the art, andwill not be described in detail here.

According to an embodiment in a third aspect of the present application,an energy storage device is provided, which includes the battery packaccording to the embodiment in the first aspect of the presentapplication.

The battery pack 10 according to the embodiments of the presentapplication and the improvements in the energy density and other aspectseffected by the designs of the arrangement and size parameters of thecell 100 are described by Comparative Embodiment 1, Embodiments 1-3,Comparative Embodiment 2 and Embodiments 4-5.

In the following embodiments and comparative embodiments, description ismade with lithium iron phosphate battery as an example.

In Comparative Embodiment 1, Embodiment 1, Embodiment 2, and Embodiment3, the total volume of the battery pack 10′ is 213 L, and the totalvolume occupied by the housing 200′, the internal battery managementsystem and other power distribution modules is 58 L. Therefore, theactual volume remaining in the battery pack 10′ for accommodating thecells, the width-direction transverse beam, and the length-directiontransverse beam is 155 L. The volume of the power distribution box is22.5 L, the length of the housing 200′ is 1380 mm, the width is 1005 mm,and the thickness is 137 mm. The total volume of the battery pack is 213L=1380×1005×137×0.000001+22.5.

Comparative Embodiment 1

In the battery pack 10′ provided in the prior art, as shown in FIG. 1,the housing 200″ is provided with two width-direction transverse beams500′ and one length-direction transverse beam 600′ therein. The twowidth-direction transverse beams 500′ and one length-directiontransverse beam 600′ divide the cells into six battery modules 400′, andeach battery module 400′ has a battery module housing.

Embodiment 1

In the battery pack 10 according to this embodiment of the presentapplication, as shown in FIG. 12, the length direction of the cell 100is arranged along the width direction B of the battery pack, and aplurality of cells 100 are arranged along the length direction A of thebattery pack 10. In the width direction B of the battery pack, thehousing 200 accommodates two cells 100. The housing 200 is provided withone width-direction transverse beam 500 and one length-directiontransverse beam 600 therein. The width-direction transverse beam 500extends along the width direction B of the battery pack 10, and theplurality of cells 100 are arranged along the length direction A of thebattery pack 10 to form a battery array. The width-direction transversebeam 500 divides the battery array into at least two parts along thelength direction A of the battery pack 10. In addition, the plurality ofcells 100 are arranged into two rows of battery arrays along the widthdirection B of the battery pack, and the length-direction transversebeam 600 is located between the two adjacent rows of battery arrays. Thefirst side beam 201 and the second side beam 202 of the housing 200located at two sides of the battery pack 10 in the width direction Bprovide support for the cells 100, and the first end beam 203 and thesecond end beam 204 of the housing 200 located at two ends of thebattery pack 10 in the length direction A provide an inward pressingforce against adjacent cells 100. The housing 200 includes a layer ofbattery array along the height direction C of the battery pack 10. Thebattery array (also known as battery module) of the battery pack 10 doesnot provided with end beams and side beams.

Embodiment 2

In the battery pack 10 according to this embodiment of the presentapplication, as shown in FIG. 13, the length direction of the cell 100is arranged along the width direction B of the battery pack, and aplurality of cells 100 are arranged along the length direction A of thebattery pack 10. In the width direction B of the battery pack, thehousing 200 accommodates one cell 100. The cell 100 extends from oneside to the other side of the housing 200 in the width direction B ofthe battery pack 10. The housing 200 is provided with onewidth-direction transverse beam 500, but no length-direction transversebeam 600 therein. The width-direction transverse beam 500 extends alongthe width direction B of the battery pack 10, and the plurality of cells100 are arranged along the length direction A of the battery pack 10 toform a battery array. The width-direction transverse beam 500 dividesthe battery array into two parts along the length direction A of thebattery pack 10. The first side beam 201 and the second side beam 202 ofthe housing 200 located at two sides of the battery pack 10 in the widthdirection B provide support for the cells 100, and the first end beam203 and the second end beam 204 of the housing 200 located at two endsof the battery pack 10 in the length direction A provide an inwardpressing force against adjacent cells 100. The housing 200 includes alayer of battery array along the height direction C of the battery pack10. The battery array (also known as battery module) of the battery pack10 does not provided with end beams and side beams.

Embodiment 3

In the battery pack 10 according to this embodiment of the presentapplication, as shown in FIG. 14, the length direction of the cell 100is arranged along the width direction B of the battery pack, and aplurality of cells 100 are arranged along the length direction A of thebattery pack 10. In the width direction B of the battery pack, thehousing 200 accommodates one cell 100. The cell 100 extends from oneside to the other side of the housing 200 in the width direction B ofthe battery pack 10. No width-direction transverse beam 500 andlength-direction transverse beam 600 are provided in the housing 200.The first side beam 201 and the second side beam 202 of the housing 200located at two sides of the battery pack 10 in the width direction Bprovide support for the cells 100, and the first end beam 203 and thesecond end beam 204 of the housing 200 located at two ends of thebattery pack 10 in the length direction A provide an inward pressingforce against adjacent cells 100. The housing 200 includes a layer ofbattery array along the height direction C of the battery pack 10. Thebattery array (also known as battery module) of the battery pack 10 doesnot provided with end beams and side beams.

It can be known by those skilled in the art through comparison ofComparative Embodiment 1 and Embodiments 1-3 that compared with thebattery pack 10′ in the prior art, the battery pack 10 according to theembodiment of the present application has a space utilization breakingthrough the limitations of the existing battery packs by the designs ofthe arrangement of the cells 100, the size parameters and other factors,thereby achieving a higher energy density.

In Comparative Embodiment 2, Embodiment 4 and Embodiment 5, the totalvolume of the battery pack 10′ is 283 L, and the total volume occupiedby the housing 200′, the internal battery management system and otherpower distribution modules is 89 L. Therefore, the actual volumeremaining in the battery pack 10′ for accommodating the cells and/or thelength-direction transverse beam and the width-direction transverse beamis 221 L. The length of the housing 200″ is 1380 mm, the width is 1380mm, and the thickness is 137 mm; and the cell length is 215 mm, and thewidth is 118 mm, and the height is 13.5 mm. The volume of the powerdistribution box is 11 L, and the total volume of the battery pack is310 L=1580×1380×137×0.000001+11.

Comparative Embodiment 2

In the battery pack 10′ provided in the prior art, as shown in FIG. 1,the housing 200″ is provided with two width-direction transverse beams500′ and one length-direction transverse beam 600′ therein. The twowidth-direction transverse beams 500′ and one length-directiontransverse beam 600′ divide the cells into six battery modules 400′, andeach battery module 400′ has side beams and end beams.

Embodiment 4

In the battery pack 10 according to this embodiment of the presentapplication, as shown in FIG. 15, the length direction of the cell 100is arranged along the length direction A of the battery pack, and aplurality of cells 100 are arranged along the width direction B of thebattery pack 10. In the length direction A of the battery pack, thehousing 200 accommodate one cell 100. The cell 100 extends from one sideto the other side of the housing 200 in the length direction A of thebattery pack 10. The housing 200 is provided with one length-directiontransverse beam 600, but no width-direction transverse beam 500 therein.The length-direction transverse beam 600 extends along the lengthdirection A of the battery pack 10, and the plurality of cells 100 arearranged along the width direction B of the battery pack 10 to form abattery array. The length-direction transverse beam 600 divides thebattery array into two parts along the width direction B of the batterypack 10. The first end beam 203 and the second end beam 204 of thehousing 200 located at two ends of the battery pack 10 in the lengthdirection A provide support for the cells 100, and the first side beam201 and the second side beam 202 of the housing 200 located at two sidesof the battery pack 10 in the width direction B provide an inwardpressing force against adjacent cells 100. The housing 200 includes alayer of battery array along the height direction C of the battery pack10. The battery array (also known as battery module) of the battery pack10 does not provided with end beams and side beams.

Embodiment 5

In the battery pack 10 according to this embodiment of the presentapplication, as shown in FIG. 16, the length direction of the cell 100is arranged along the length direction A of the battery pack, and aplurality of cells 100 are arranged along the width direction B of thebattery pack 10. In the length direction A of the battery pack, thehousing 200 accommodates one cell 100, and the cell 100 extends from oneside to the other side of the housing 200 in the length direction A ofthe battery pack 10. No width-direction transverse beam 500 andlength-direction transverse beam 600 are provided in the housing 200.The first end beam 203 and the second end beam 204 of the housing 200located at two ends of the battery pack 10 in the length direction Aprovide support for the cells 100, and the first side beam 201 and thesecond side beam 202 of the housing 200 located at two sides of thebattery pack 10 in the width direction B provide an inward pressingforce against adjacent cells 100. The housing 200 includes a layer ofbattery array along the height direction C of the battery pack 10. Thebattery array (also known as battery module) of the battery pack 10 doesnot provided with end beams and side beams.

In Comparative Embodiment 3, and Embodiment 6, the total volume of thebattery pack 10′ is 414 L, and the total volume occupied by the housing200′, the internal battery management system and other powerdistribution modules is 58 L. Therefore, the actual volume remaining inthe battery pack 10′ for accommodating the cells and/or thelength-direction transverse beam and the width-direction transverse beamis 356 L. The length of the housing 200′ is 2130 mm, the width is 1380mm, and the thickness is 137 mm. The volume of the power distributionbox is 11 L, and the total volume of the battery pack is 414L=2130×1380×137×0.000001+11.

Comparative Embodiment 3

The arrangement of cells is the same as that in Comparative Embodiment1.

Embodiment 6

The arrangement of cells in the battery pack is the same as that inEmbodiment 5.

Embodiment 7

In this embodiment, the total volume of the battery pack 10′ is 508 L,and the total volume occupied by the housing 200′, the internal batterymanagement system and other power distribution modules is 119 L.Therefore, the actual volume remaining in the battery pack 10′ foraccommodating the cells and/or the length-direction transverse beam andthe width-direction transverse beam is 389 L. The length of the housing200″ is 2630 mm, the width is 1380 mm, and the thickness is 137 mm. Thevolume of the power distribution box is 11 L, and the total volume ofthe battery pack is 414 L=2630×1380×137×0.000001+11. The arrangement ofcells in the battery pack is the same as that in Embodiment 5.

The specific parameters of Embodiments 1-7, and Comparative Embodiments1-3 are shown in Table 1. The total cell volume is the sum of thevolumes of multiple cells; the volume of the battery pack is the overallvolume of a three-dimensional shape defined by an external profile ofthe battery pack, that is, the volume of the three-dimensional areaenclosed in space by the external profile of the battery pack; and thevolume of the cell accommodating cavity is the volume of theaccommodating space defined in the housing.

TABLE 1 Sum of Total Energy volumes Power volume density of cells/ Sizeof cell: Energy of of of volume length, width, Capacity Power Volumedensity battery battery battery of battery and height of cell of cell ofcell of cell pack pack pack pack (mm) Number (Ah) (Wh) (L) (Wh/L) (Wh)(L) (Wh/L) (%) Comparative  208*118*13.5 352 47.5 152 0.331 459 53504213 251 54.76% Embodiment 1 Embodiment 1  435*118*13.5 176 95 304 0.693439 53504 213 252 57.39% Embodiment 2  905*118*13.5 88 202 646.4 1.442448 56883 213 268 59.70% Embodiment 3  905*118*13.5 92 202 646.4 1.442448 59469 213 280 62.41% Comparative  208*118*13.5 500 47.5 152 0.331459 76000 310 245 53.49% Embodiment 2 Embodiment 4 1280*118*13.5 90 286915.2 2.039 449 82368 310 266 59.25% Embodiment 5 1280*118*13.5 93 286915.2 2.039 449 85114 310 275 61.23% Comparative  208*118*13.5 752 47.5152 0.331 459 114304 414 276 60.23% Embodiment 3 Embodiment 62000*118*13.5 94 448 1434 3 450 134758 414 326 72.39% Embodiment 72500*118*13.5 94 561 1795 4 451 168749 508 332 73.66%

It can be known by those skilled in the art through comparison of thecomparative embodiments and the embodiments of the present applicationthat the battery pack 10 according to the embodiment of the presentapplication has a space utilization breaking through the limitations ofthe existing battery packs by the designs of the arrangement of thecells 100, the size parameters and other factors, thereby achieving ahigher energy density. Moreover, this increase in the energy densitywill be enlarged as the overall volume of the battery pack increases.That is, for a battery pack with a larger volume, the improvement inenergy density effected by the solution in the embodiments of thisapplication is more significant.

In description of this specification, description of reference termssuch as “specific embodiments”, or “specific examples”, means includingspecific features, structures, materials, or features described in theembodiment or example in at least one embodiment or example of thisapplication. In this specification, exemplary descriptions of theforegoing terms do not necessarily refer to the same embodiment orexample.

Although the embodiments of this application have been shown anddescribed, a person of ordinary skill in the art should understand thatvarious changes, modifications, replacements and variations may be madeto the embodiments without departing from the principles and spirit ofthis application, and the scope of this application is as defined by theappended claims and their equivalents.

What is claimed is:
 1. A battery pack, comprising: a housing; aplurality of cells, provided in the housing; wherein the sum V1 of thevolumes of the plurality of cells and the volume V2 of the battery packsatisfy V1/V2≥55%; and the battery pack has a first direction and asecond direction perpendicular to each other; a length direction of thecell is arranged along the first direction of the battery pack, and theplurality of cells are arranged along the second direction of thebattery pack; the housing accommodates only one cell along the firstdirection; and the cell comprises a cell body, and the length of thecell body is 600-2500 mm. 2.-4. (canceled)
 5. The battery pack accordingto claim 1, wherein the first direction is a width direction of thebattery pack, and the second direction is a length direction of thebattery pack; the length direction of the cell is arranged along thewidth direction of the battery pack, and the plurality of cells arearranged along the length direction of the battery pack.
 6. The batterypack according to claim 5, wherein the housing accommodates only onecell in the width direction of the battery pack.
 7. The battery packaccording to claim 5, wherein in the width direction of the batterypack, a shortest distance from one end of the cell to a side beam of thehousing adjacent to the end of the cell is L1, a shortest distance fromthe other end of the cell to a side beam of the housing adjacent to theother end of the cell is L2, and the length L of the cell satisfies:L1+L2<L.
 8. The battery pack according to claim 5, wherein along thewidth direction of the battery pack, the cell extends from one side tothe other side of the housing.
 9. The battery pack according to claim 6,wherein at least one width-direction transverse beam extending along thewidth direction of the battery pack is provided in the housing, theplurality of cells are arranged along the length direction of thebattery pack to form a battery array, the width-direction transversebeam divides the battery array into at least two parts along the lengthdirection of the battery pack, and each part of the battery arraycomprises at least one cell.
 10. The battery pack according to claim 5,wherein the length direction of the cell is arranged along the widthdirection of the battery pack, the plurality of cells are arranged alongthe length direction of the battery pack to form a battery array, atleast two rows of battery arrays are arranged in the housing along thewidth direction of the battery pack, at least one length-directiontransverse beam extending along the length direction of the battery packis provided in the housing, and the length-direction transverse beam islocated between two adjacent rows of battery arrays.
 11. The batterypack according to claim 6, wherein the housing comprises side beamslocated at two sides of the battery pack in the width direction, and twoends of the cell in the length direction are supported by the sidebeams; and the housing comprises end beams located at two ends of thebattery pack in the length direction, and the end beams provide aninward pressing force against cells adjacent to the end beams.
 12. Thebattery pack according to claim 1, wherein the first direction is awidth direction of the battery pack, and the second direction is alength direction of the battery pack; the length direction of the cellis arranged along the width direction of the battery pack, and theplurality of cells are arranged along the length direction of thebattery pack to form a battery array; and at least two layers of batteryarrays are provided in the housing along a height direction of thebattery pack.
 13. The battery pack according to claim 1, wherein thefirst direction is a width direction of the battery pack, and the seconddirection is a length direction of the battery pack; and the lengthdirection of the cell is arranged along the length direction of thebattery pack, and the plurality of cells are arranged along the widthdirection of the battery pack.
 14. The battery pack according to claim13, wherein the housing accommodates only one cell in the lengthdirection of the battery pack.
 15. The battery pack according to claim13, wherein in the length direction of the battery pack, a shortestdistance from one end of the cell to an end beam of the housing adjacentto the end of the cell is L3, a shortest distance from the other end ofthe cell to an end beam of the housing adjacent to the other end of thecell is L4, and the length L of the cell satisfies: L3+L4<L.
 16. Thebattery pack according to claim 13, wherein along the length directionof the battery pack, the cell extends from one end to the other end ofthe housing.
 17. The battery pack according to claim 14, wherein atleast one length-direction transverse beam extending along the lengthdirection of the battery pack is provided in the housing, the pluralityof cells are arranged along the width direction of the battery pack toform a battery array, the length-direction transverse beam divides thebattery array into at least two parts along the width direction of thebattery pack, and each part of the battery array comprises at least onecell.
 18. The battery pack according to claim 13, wherein the lengthdirection of the cell is arranged along the length direction of thebattery pack, the plurality of cells are arranged along the widthdirection of the battery pack to form a battery array, at least two rowsof battery arrays are arranged in the housing along the length directionof the battery pack, at least one width-direction transverse beamextending along the width direction of the battery pack is provided inthe housing, and the width-direction transverse beam is located betweentwo adjacent rows of battery arrays.
 19. The battery pack according toclaim 14, wherein the housing comprises ends beams located at two endsof the battery pack in the length direction, and two ends of the cell inthe length direction are supported by the end beams; and the housingcomprises two side beams located at two sides of the battery pack in thewidth direction, and the side beams provide an inward pressing forceagainst cells adjacent to the side beams.
 20. The battery pack accordingto claim 14, wherein the length direction of the cell is arranged alongthe length direction of the battery pack, and the plurality of cells arearranged along the width direction of the battery pack to form a batteryarray; and at least two layers of battery arrays are provided in thehousing along a height direction of the battery pack.
 21. The batterypack according to claim 1, wherein the housing includes a vehicle traythat is fitted and connected to the vehicle body.
 22. The battery packaccording to claim 1, wherein a width F of the housing in the widthdirection of the battery pack is 500-1500 mm.
 23. (canceled)
 24. Thebattery pack according to claim 1, wherein the housing is formed on anelectric vehicle.
 25. (canceled)
 26. The battery pack according to claim1, wherein the cell comprises a cell body, and the cell body has alength L, a width H and a thickness D, wherein the length L of the cellbody is greater than the width H, the width H of the cell body isgreater than the thickness D, and the length L and the width H of thecell body satisfy L/H=4-21, and the length L of the cell body and thethickness D of the cell body satisfy L/D=23-208.
 27. (canceled)
 28. Thebattery pack according to claim 1, wherein the cell body has a length Land a volume V, and the length L of the cell body and the volume V ofthe cell body satisfy L/V=0.0005 mm⁻²-0.002 mm⁻².
 29. The battery packaccording to claim 1, wherein the cell body has a width H and a volumeV, and the width H of the cell body and the volume V of the cell bodysatisfy H/V=0.0001 mm⁻²-0.00015 mm⁻².
 30. The battery pack according toclaim 1, wherein the cell body has a thickness D and a volume V, and thethickness D of the cell body and the volume V of the cell body satisfyD/V=0.0000065 mm⁻²-0.00002 mm⁻².
 31. The battery pack according to claim1, wherein the cell body has a length L and a surface area S, and thelength L of the cell body and the surface area S of the cell bodysatisfy L/S=0.002 mm⁻¹-0.005 mm⁻¹.
 32. The battery pack according toclaim 1, wherein the cell body has a surface area S and a volume V, andthe surface area S of the cell body and the volume V of the cell bodysatisfy S/V=0.1 mm⁻¹-0.35 mm⁻¹.
 33. The battery pack according to claim1, wherein the cell body has a length L of 700-2500 mm.
 34. The batterypack according to claim 33, wherein the cell body has a length L of800-1500 mm. 35.-44. (canceled)